Response of Marine Microalgae Tetraselmis chuii to 5 Groups of Antibiotics

Antibiotic contamination in aquatic environments, as well as its effects on non-target organisms, has recently come to the attention of researchers. In the current study, three dosages (1, 0.5, and 0.25mg/L) of five antibiotic groups were tested on the marine green microalgae T. chuii: quinolones, tetracyclines, penicillins, macrolides, and sulfanamides. As stress biomarkers, cell density, dry biomass, specific growth rate, and chlorophyll content were calculated. Tetracyclines, penicilines, and sulfonamide in all doses inhibited algal growth. Among Quinolones, Ciprofloxacin and Enrofloxacin stimulated green algae growth at all tested dosages, whereas 1mg/l of Levofloxacin and Nalidilic acid inhibited it slightly while the other dosages stimulated it. Similar results were obtained for Macrolides: all three Erythromycin dosages were toxic to T.chuii, while 1mg/L was not. Similar results were obtained for Macrolides: all three Erythromycin dosages were toxic to T.chuii; while 1mg/L of Tylosin stimulated algal growth, lower dosages inhibited it. As a result, antibiotic pollution may alter the aquatic environment not only by reducing or inhibiting the growth of one species, but also by stimulating the growth of others, resulting in ecological imbalance and, as a result, the food chain. Using specific antibiotics in specific dosages in microalgae farms, on the other hand, could increase biomass while decreasing microbial contaminations.